Self-exciting alternator.



.PATENTED JUNE 4, 1907.

L. I. LE PONTOIS. SELF EXCITING ALTERNATOR.

APPLIOATION TILED DEC. 11, 1905.

2 SHEETBBHBET 1.

No. 855,713. PATENTED JUNE 4, 1907. L. J. LB PONTOIS.

SELF EXCITING ALTERNATOR.

APPLIGATION FILED DEO.11,1905.

2 SHEBTS-SHEET 2.

Angsts I 0a r ATTORNEY i poles surrounded by cause the rate at whichthereluctance of the UNITED STATES PATENT OFFICE. LEON LE ro 'ro'rsI or Newnoonannn, NEW PQLYQPIIASE .IGNITIGN SYSTEM COIVIPANY, A YORK."

YORK, ASSIGNOR TO CORPORATION OF NEW szLF- sxosrme ALTERNATOR.

Specification of il' etters latent. Patented 'il'une, 190?. e iieeeienfiled December 1 1, 1905; "senel No. 291.262. I Y

necsmia To all whom itfmay concern: I I Be it known that I, LEON J. LuPONTOIS, a citizen of the Republic of France, and a resiilent of NewRochelle, Westchester county, New York, haveinvented certain new anduseful Improvements in Self-Exciting Alternators', of which thefollowingis a specification. I 4

In my Patent-808,555 dated December 26, 1905, I have described analternating current magneto of the inductor type designed primarily todeliver suitable currents to socalled spark coils usedfor theignition ofexplosive mixtures tern, said magneto resenting a very portant feature,in tli at, without the use of .rectifying means the alternating currentgeneratedwas partially utilized in maintaining the so-called permanentmagnets, constituting the field of the magneto to a really ence to whichv.

Figure 1 is a central vertical the plane of the line lel of Fig. 2;.Fig. 2 is a horizontal section onftheplane of the line 2 -2 of 1; Fig.is a diagrammatic view.

the accompanying drawings in .Similar reference numerals indicatesimilar parts throughout the several views Referring to the drawings thenumeral 1 designates a base of suitable material upon which are mountedsaid p prevent eddy currents, and held rigidly apart from each other bytwo nonmagnetic end plates 3 and 4 through which I pass suitable bolts5. Permanent magnets The rotation of this proximity to magnetic properwindings caused the alternating currents induced in these windings toreach cured by su1table means against the outer ar projections 2,developing jections two A plate 7 bridges the u per part of thestructure to properly inc ose the armature in a dust proof case.

he armature 8 is preferably formed of a number of soft iron laminaesecured together insulated rivets .9 and after being assembliedare keyedto the The form of The polar surfaces10 and 10 oppositely located oneach side of the axial line are substantially circular in shape, whilethe oppositely located polar surfaces 11 and 11 are not concentric. Thepolar surfaces 10 and 10 being substantially circular in shape the edges21 different intensities bemagnetic field threading through thesereluctance of the same magnetic field was decreased. It is obvious thatunder the above conditions that one of the two currents reaching valuehas rents tending to field or to maintain it at least to a fairlypermanent state of magnetization.

The object of-the present invention is to apply this same principle tothe magnetization of the permanent magnets of the alternating type ofshuttle wound Siemens magn degrees the air ga It s known that the rotating element of this (1 between the poles N and S and the polar surfaces11-11 of the armature, which is initially very large, will graduallydecrease until the armature has com leted its rotation through 90degrees. It will follow, therefore, that the reluctance of the Theinvention will be understobd l ly-refer section on 6, four being shownin the drawings, are semagnetic flux induced by the permanent reason Ilocate two auxiliary field coils 20 on magnets in the magnetic circuit,comprising the edges of the poles N and 'S, which coils themselves, thepolar pro ections are in series with each other and are prefer- Z2, theair gaps between the armature and said polar projections, and thearmature, will decrease very gradually, attaining its minimum when thearmature reaches a position at right angles to that-shown. When thearmature rotates from this latter position to the position shown in Fig.1 the magnetic reluctance of the field will increase at a very slow rateup to the point where the polar surfaces 10-10 abruptly leave the edgesof the poles N and S. It will be seen by the drawing that the air gapincreases very suddenly with a slight angular motion of the armature.

Upon the armature 8 is wound a coil 12 in the usual manner and protectedby suitable insulation 13. One terminal of the winding is grounded, theother terminal being led through an insulatedbushing 14 to a conpin 15secured in the hollow shaft 22 and insulated therefrom by a bushing 16.A. brush 17 insulated from the cap 4 is pressed against revolving pin 15by a spring 18 in electrical connection with a binding post 19.

From the above description it will be seen that an alternating currentwave will e generated in the armature circuit while it rotates in thedirection of the arrow from the position shown in Fig. 1 to a positionat right angles thereto. During that period of rotation the intensity ofthe magnetic fiux threading through the armature coil will increaserogressively from zero to a maximum va ue, but as this increase is veryradual the current wave may be represented by the curve a of Fig. 8.During the retation of the armature from this last de scribed positionto that shown in Fig. 1 the magnetic flux threading through the armaturecoil'will at first decrease very slowly, but as the armature ap roachesthe edges of the oles N and S it decrease abruptly caus ing thereby asudden and rapid increase in the rate of change of the intensity of themagnetic flux threading through the coil 12 and a subsequent sudden risein value of the current induced in the armature coil. It will be noticedthat the field created in the armature by this induced current tends toincrease the intensity of the total magnetic flux issuing from thepermanent magnets, but owing to the fact that when that auxiliary fieldexcitation takes place the axis of the armature forms a considerableangle with the axis of the permanent magnetic flux, the auxiliarymagnetization is not felt as well by the permanent magnetic field as ifthe axis of both fields coincided. For this ably connected in shuntacross the armature circuit as shown in Fig. 4. In order to increase themagnetizing effect' of these auxiliary coils upon the total field Iadvance the phase of the current flowing through said auxiliary coils byplacing a condenser 23 in shunt with them thus causing the maximumcurrent to take place while the armature edges 21 and 21 being in closeproximity to the edges of the poles N andS presents a fiirly goodmagnetic path for the auxiliary The shaft 22 may be driven from anysuitable source of power through a gear 24.

What I claim and desire to secure by Letters Patent is:

1. A partially self exciting alternator having a-permanent magneticfield, polar projections of soft iron adjacent to the magnetic polesdeveloped by said field, a rotor having dissymmetric polar faces adaptedto rotate ducting soft iron polar projections said coils being connectedin series with each other and in shunt with said rotor winding, wherebythe waves of the alternating current generated which have a magnetizingeffect on the permanent magnetic field reach a higher value than thosewhich have feet on said field and the magnetizing effect being increasedby the location of theauxiliary windings in the magnetic circuit.

2. A partially self exciting alternator having a permanent magneticfield, polar projections of soft iron adjacent to the magnetic polesdeveloped by said field, a rotor having dissymmetric polar faces adaptedto rotate in close proximity to said poles, a winding on said rotorauxiliary coils wound around said soft iron polar projections saidcoils' being connected in series with each other and in shunt with saidrotor windings, and a condenser connected in shunt with said auxiliarycoils, whereby the phase of the auxiliary magnetizing current issufficiently advanced to enable the auxiliary magnetic field thus set upto exert its action on the main field while the rotor by its position inthe field presents a path of sufficiently low magnetic reluctance.

In testimony whereof I have hereunto signed my name in the presence oftwo subscribing witnesses.

. LEON J. LE PONTOIS. Witnesses:

'OLIN AuFo's'rnn, GEORGE W. Youuo.

in close proxim1 t'y to said poles, a winding on said rotor auxiliaryCOIlS'WOUIld around saida demagnetizing ef-

